Ionic Properties of Hydrous Oxide Gels

1992 ◽  
Vol 293 ◽  
Author(s):  
J. Livage
Keyword(s):  
Electrode Materials ◽  
Sol Gel ◽  
Adsorbed Water ◽  
Solid Particles ◽  
Strong Interactions ◽  
Water Molecules ◽  
Electrochromic Devices ◽  
Hydrous Oxides ◽  
Ordered Phases ◽  
Sol Gel Process

AbstractThe sol-gel process offers new opportunities for the synthesis of ionic materials, specially in the shape of thin films. Hydrous oxides are obtained which exhibit specific properties arising from strong interactions betwwen adsorbed water molecules and the oxide network. Sol-gel derived coatings are good candidates as electrode materials for lithium batteries or electrochromic devices. Their open structure allows easier diffusion of Li+ions in the liquid phase while electrons are delocalized through the oxide network. Moreover, water molecules favor the formation of ordered phases leading to the deposition of layers with preferred orientation. Electrochemical insertion can then be described as an intercalation process between solid particles.

Synthesis and Characterization of Organic Dye Doped Silica Glasses

1992 ◽  
Vol 271 ◽  
Author(s):  
Ilzoo Lee ◽  
Josephine Covino ◽  
Michael D. Seltzer
Keyword(s):  
Organic Dyes ◽  
Sol Gel ◽  
Adsorbed Water ◽  
Alcohol Solution ◽  
Water Molecules ◽  
Dye Molecules ◽  
Silica Glasses ◽  
Sol Gel Process ◽  
Higher Temperature

ABSTRACTThe sol-gel process was used to incorporate organic dyes including Rhodamine 6G (Rh6G), 2-(4-pyridyl)-5-(4-phenyl) oxazole (4PyPO) and the n-methyl tosylate salt of 2-(4-pyridyl)-5-(4-methoxy phenyl)oxazole (4PyMPO-MePTS) in silica gel. Thermogravimetric analysis (TGA) and differential scanning calorimeter (DSC) analysis of the dye doped gels showed that the gel structure loses the adsorbed water molecules from room temperature to 150°C and decomposition of the dye molecules followed at the higher temperature. Absorption and emission of the dyes in the sol-gel glass matrix were also studied and compared with the results of the dyes in alcohol solution. The environments of the dye in silica were different than in alcohol solution.

Synthesis of Hollow Titania Photocatalytic Particles Using Yeast as Templates

2013 ◽  
Vol 699 ◽  
pp. 126-132 ◽  
Author(s):  
Toshiyuki Nomura ◽  
Syota Tanii ◽  
Hayato Tokumoto ◽  
Yasuhiro Konishi
Keyword(s):  
Pore Diameter ◽  
Sol Gel ◽  
Solid Particles ◽  
Core Shell ◽  
Average Pore ◽  
Inorganic Particles ◽  
Sol Gel Process ◽  
Yeast Powder ◽  
Titania Precursor ◽  
Hydrolysis Of

Hollow inorganic particles have attracted considerable interest for a variety of applications. In this work, yeast powder was used as a bio-template to fabricate yeast/titania core-shell spheres. A titania precursor was deposited via the hydrolysis of tetraisopropyl titanate. Triethanolamine was employed to control the reaction rate of the sol-gel process. The hollow titania particles with a diameter of approximately 4 m and a thickness of approximately 54 nm were successfully obtained after calcination of the core-shell spheres at 700 °C. The crystal structure of the particles was anatase. The specific surface area and the average pore diameter were 21.4 m2/g and 1.6 nm, respectively. The photocatalytic activity of the hollow particles was higher compared with that of solid particles.

Novel Electrode Materials for Ultracapacitors:Structural and Electrochemical Properties of Sol-Gel-Derived Manganese Dioxide Thin Films

1999 ◽  
Vol 575 ◽  
Author(s):  
Suh-Cern Pang ◽  
MarcA Anderson
Keyword(s):  
Thin Films ◽  
Specific Capacitance ◽  
Electrode Materials ◽  
Sol Gel ◽  
High Specific Capacitance ◽  
Potential Range ◽  
Proton Mobility ◽  
Reversible Redox ◽  
Sol Gel Process ◽  
Nickel Substrates

ABSTRACTNanoparticulate MnO2thin films fabricated by the sol-gel process have been shown to be an outstanding novel electrode material for Ultracapacitors. The average specific capacitance of sol-gel-derived MnO2thin-films on nickel substrates as determined by cyclic voltammetry ranged from 566 to 698 F/g. These films also exhibited good cycling stability within the potential range of 0.0-0.9V (vs SCE) in unbuffered aqueous electrolyte. Both CV and XPS studies showed that MnO2films have remained chemically and structurally intact after 1,500 cycles. The XRD spectra and SEM micrographs showed that the microstructure of MnO2thin films are highly porous, and poorly crystalline or amorphous in nature. The high specific capacitance of MnO2may be predominantly due to pseudocapacitance associated with homogenous and reversible redox reactions of proton insertion into and out of the MnO2lattice. Any variation in the microstructure and thickness of films might affect proton mobility within the oxide matrix and thereby affecting their cycling behaviors. Further optimization of the cycling behaviors is envisaged with better microstructural and thickness control of these sol-gelderived nanoparticulate MnO2thin films.

scholarly journals Sol-Gel Coatings for Electrochromic Devices

1992 ◽  
Vol 276 ◽  
Author(s):  
M. A. Macedo ◽  
L. H. Dall'Antonia ◽  
M. A. Aegerter
Keyword(s):  
Heat Treatment ◽  
Sol Gel ◽  
Radiant Energy ◽  
Electrochromic Devices ◽  
Smart Windows ◽  
Ito Glass ◽  
Sol Gel Process ◽  
Ion Storage ◽  
Potential Applications ◽  
Transmission And Reflection

ABSTRACTAll solid state electrochromic smart windows with the configuration glass/ITO/WO3/electrolyte/TiO2-CeO2/ITO/glass have been realized. These devices have potential applications in architectural and automotive fields to regulate the transmission and reflection of the radiant energy. The ion storage electrode TiO2–CeO2 have been realized by sol-gel process and its electrochemical properties are studied as a function of various parameters (thickness, heat treatment, etc.). The electrochemical and optical performances of two cells are reported.

Synthesis and Electrochemical characterization of LiNi1-yCoyO2 powders obtained by complex sol-gel process

1999 ◽  
Vol 575 ◽  
Author(s):  
F. Croce ◽  
A. D'Epifanio ◽  
A. Deptula ◽  
W. Lada ◽  
A. Ciancia ◽  
...  
Keyword(s):  
Ascorbic Acid ◽  
Solid Solutions ◽  
Electrode Materials ◽  
Thermal Transformation ◽  
Sol Gel ◽  
Lithium Ion ◽  
Cell Voltage ◽  
High Energy ◽  
High Energy Density ◽  
Sol Gel Process

ABSTRACTThe layered oxides, among the wide family of intercalation compounds, have received considerable attention as positive electrode materials in high-energy density lithium and lithium ion batteries. Within this frame LiNiO2 and LiCoO2 oxides and their solid solutions have been extensively studied as they (and the LiMn2O4 spinels) are the only known materials able to intercalate reversibly lithium at high cell voltage (3.5-4 V). Recently, solid solutions such as LiNi1-xCoxO2 have attracted the attention as alternative cathodes to the state of art LiCoO2 in commercial rechargeable Li-ion batteries. Here we have used the Complex Sol-Gel Process (CSGP) to prepare LiNi1-xCoxO2 (x= 0, 0.25, 0.5, 0.75, 1). Starting sols were prepared from Li+-(1-x)Ni2+-xCo2+ acetate aqueous solution in two different routes. According to route-A aqueous ammonia was added to a starting solution containing 0.2M ascorbic acid (ASC) on 1 M total Me. According to route B the starting acetate solutions were first alkalized by ammonia and then the ascorbic acid was added. Regular sols were concentrated to 1/3 of their initial volume and dried slowly up to 170°C. Thermal transformation of the gels to solids was studied by XRD and IR. The electrochemical properties of the compound LiNi0.75Co0.25O2 prepared by the Route-A were evaluated and reported.

Sol-Gel Derived Pyroelectric Barium Strontium Titanate Thin films for Infrared Detector Applications

2000 ◽  
Vol 655 ◽  
Author(s):  
Jian-Gong Cheng ◽  
Jun Tang ◽  
Shao-Ling Guo ◽  
Jun-Hao Chu
Keyword(s):  
Thin Films ◽  
Electrode Materials ◽  
Infrared Detector ◽  
Sol Gel ◽  
Precursor Solution ◽  
Columnar Structure ◽  
Silicon Substrates ◽  
Layer By Layer ◽  
Individual Layer ◽  
Sol Gel Process

AbstractBa0.8Sr0.2TiO3 thin films that are suitable for infrared detector applications have been prepared with a sol-gel process using a highly diluted precursor solution. Columnar structure with grain size close to 200 nm was obtained with layer-by-layer homoepitaxy due to a very small thickness of individual layer. The measured pyroelecrtic coefficient is larger than 3.1×10划4 C/m2K at the temperatures ranging from 10 to 26 °C and reaches the maximum value of 4.1×10划4 C/m2K at 16.8 °C. The infrared detectivity of 4.6×107 cmHz1/2W划1 has been obtained at 19 °C and 10 Hz in the Ba0.8Sr0.2TiO3 films deposited on thick (500 μm) platinum coated silicon substrates. The better infrared response can be expected by the improvement in the thermal isolation of pyroelectric element and the electrode materials.

Ionic Properties of Vanadium Pentoxide Gels

1988 ◽  
Vol 121 ◽  
Author(s):  
J. Livage ◽  
P. Barboux ◽  
J. C. Badot ◽  
N. Baffier
Keyword(s):  
Vanadium Pentoxide ◽  
Water Adsorption ◽  
Mixed Valence ◽  
Adsorbed Water ◽  
Water Molecules ◽  
Proton Diffusion ◽  
Hydrous Oxides ◽  
Solution Interface ◽  
Ionic Devices ◽  
Acid Aqueous Medium

ABSTRACTVanadium pentoxide gels V2O5·nH2O are actually hydrous oxides. Water adsorption and dissociation occurs at the surface of the oxide leading to negatively charged oxide particles surrounded by an acid aqueous medium. Ionic conductivity is observed, arising from proton diffusion through the water molecules. This process mainly depends on the nature of adsorbed water molecules. Proton conductivity is strongly related to the water adsorption isotherm.Ion exchange readily occurs at the oxide-solution interface when the gel is dipped into an aqueous solution of a metal chloride. New vanadium bronzes have been obtained upon heating such gels around 300° C. They exhibit interesting properties as reversible cathodes.Electrochemical insertion of Li* into the gel phase is quite easy. This is due to the very open structure of the gel and the mixed valence behavior of the vanadium oxide.Transition metal oxide gels could then be used as thin films or pressed pellets for making micro-ionic devices.

scholarly journals GISAXS View of Induced Morphological Changes in Nanostructured CeVO4Thin Films

2011 ◽  
Vol 2011 ◽  
pp. 1-7 ◽  
Author(s):  
Magdy Lučić Lavčević ◽  
Aleksandra Turković ◽  
Pavo Dubček ◽  
Zorica Crnjak Orel ◽  
Bojan Orel ◽  
...  
Keyword(s):  
Morphological Changes ◽  
Sol Gel ◽  
Grazing Incidence ◽  
Real Space ◽  
Electrochemical Cells ◽  
Electrochromic Devices ◽  
Lithium Ions ◽  
Glass Substrates ◽  
X Ray Scattering ◽  
Sol Gel Process

Nanostructured CeVO4films, designed for applications in electrochemical cells and electrochromic devices, were obtained on glass substrates by the sol-gel process. An analysis of morphological modifications in these films, induced by ultrasonication, annealing, and introduction of lithium ions, was performed, using the grazing-incidence small-angle X-ray scattering technique (GISAXS). The GISAXS results are discussed and related with complementary examinations of the same films in real space, performed by scanning electron microscopy on a different length scale.

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